The recommended daily intake of iodine for an average adult is 150 micrograms (µg) per day. A microgram is a one thousandth of a milligram (mg). Here we have a list of iodine rich foods and their approximate iodine content, however this varies in non-sea foods depending on the iodine content of the soil they were grown in.

Iodine rich foods

•  Sea Kelp – very high but extremely variable, can contain as much as 8000 µg of iodine in a single gram!
• Seaweed (dulse) – 100 g contains 7200 µg of iodine;  thus a 7 g (1/4 oz) serving contains 50 µg
• Iodized salt – 100 g contains 4700 µg of iodine; 1.5 g (1/4 teaspoon) contains 71 µg
• Cranberries (fresh) – 100 g contains 350 µg
• Seaweed (wakame) – 100 g contains 3200 µg of iodine
• Seaweed (nori) – often used in sushi, 100 g contains 1600 µg
• Mackerel – 100 g contains 140 µg
• Mussels – 100 g contains 100 µg
• Cod/haddock – 100 g contains 100 µg
• Sushi containing seaweed – 100 g contains approximately 92 µg
• Cheddar cheese – 100 g contains around 77 µg
• Natural yoghurt – 100 g contains around 50 µg
• White bread – Two slices contain around 45 µg
• Roast chicken – 70g (3 oz) contains around 34 µg

It is not uncommon for many people to consume a high proportion of their iodine intake through salt that is added to food. However as you can see there are many other iodine rich foods that are relatively easy to add to your diet, particularly if you are a fan of sushi or seafoods.

While iodine is vital for our bodies to function effectively, it is not required in such high quantities as many other minerals and is therefore known as a trace mineral. The normal iodine content of the adult human body is between 20 to 30 mg, and the majority of this is stored in the thyroid gland. The role of iodine in the body is to help the function of the thyroid gland. It is required for the synthesis of the thyroid hormones thyroxine (also known as tetraiodothyronine or T4) and triiodothyronine (known as T3). T4 and T3 contain four and three atoms of iodine per molecule respectively. These two hormones are vital for the regulation of various metabolic processes, in particular those involved in growth and energy expenditure but affecting all the cells in our bodies.

 

Thyroid hormones are critically important for normal development of a baby during pregnancy and essential for normal development during childhood, as well as being necessary at all life stages. You can therefore see that an iodine deficiency, brought about by a lack of iodine in the diet, can have a very detrimental effect on your health.

Iodine facts

Away from foods high in iodine, iodine is a fundamental element whose name is derived from the Greek ‘iodes’ meaning violet (it is a deep purple-black solid in its elemental state)  that has many functions other than being something that is required in the human body. These include:

• Iodine is used to test for starch in foods
• It is an ingredient in various household cleaning products
• It is used as an ingredient of antiseptics and disinfectants
• Silver iodide and Potassium iodide are traditional photographic chemicals
• Iodine has been used in the treatment of water for over 100 years
• It is a radiocontrast agent for medical imaging including CT scans and X-ray photography
• Potassium iodide can be used to reduce the harmful accumulation of radioactive substances in the thyroid following exposure to radiation.

As you can see there have been many historical uses of iodine, many of which continue to the present day. It is certainly more than just a mineral found in iodine rich foods! We hope that this explanation as to what iodine is has been of use to you, we will now proceed to explain just why iodine rich foods are needed in the human body.

Why do you need foods containing iodine?

There are several reasons why consuming iodine rich foods may be necessary, and the most obvious is to ensure you are eating a fully balanced diet. However, you may have one of several medical conditions that require an intake of iodine through preventative or treatment measures. Alternatively, you may have developed an iodine deficiency and thus will need treatment for this As always, if you are concerned, please speak to a qualified medical practitioner. For more information on this deficiency, please refer to our iodine deficiency symptoms page. Along with the other essential vitamins and minerals, iodine helps with the growth and maintenance of hair, skin, teeth and nails, so do make sure you have enough of this important mineral in your diet!